JP2002265299A - BaTiO3-PbTiO3 BASED SINGLE CRYSTAL AND MANUFACTURING METHOD THEREFOR, PIEZOELECTRIC TYPE ACTUATOR AND LIQUID DISCHARGE HEAD USING PIEZOELECTRIC TYPE ACTUATOR - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a BaTiO3 -PbTiO3 based single crystal having improved dielectric loss and electric mechanical joining coefficient, excellent piezoelectric property and low lead content, and a manufacturing method therefor. SOLUTION: The BaTiO3 -PbTiO3 based single crystal is formed by joining a seed crystal 1 composed of a BaTiO3 single crystal or a single crystal of BaTiO3 -PbTiO3 with a BaTiO3 -PbTiO3 based sintered compact 3, which is constituted of a crystal grain having <=20 μm average particle diameter and has >=95% relative density and the ratio by mole of elements ranging 0.9900<(Ba+Pb)/Ti<1.000 through the plane of (100), (110) or (111) of the seed crystal 1 and heating the joined product at 100-1400 deg.C in a non-melting state and keeping to grow the single crystal. The BaTiO3 -PbTiO3 based single crystal has 10<2> -10<6> grain/cm<2> dislocation density, 1-5 vol.% pore content and >=1 mm<3> volume.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
BaTiO available_Three -PbTiO_Three System single crystal and
And a method for producing the same.
O_Three -PbTiO _Three Actuator Consisting of Single Crystal
Discharge using the piezoelectric actuator and the piezoelectric actuator
It concerns the head.

[0002]

2. Description of the Related Art BaTiO ₃ single crystal is a non-linear optical crystal used for optical communication and information processing, and can be used for high resolution image processing, real time hologram, and phase conjugate wave generation medium for laser resonator. Rather, it is a marketable material that can be used as a high-performance piezoelectric material if low-cost crystals can be realized.

Meanwhile, BaTiO ₃ with respect to the production of single crystals, since it is difficult to single crystallization directly from BaTiO ₃ melt as can be determined from the phase diagram, the solvent mainly composed of a fluoride or chloride (flux ) Or a method of directly pulling a BaTiO ₃ single crystal having a low-temperature structure by making the melt composition rich in TiO ₂ (so-called top seeded solution growth (TSSG) method). Was.
However, in the above flux method, the size is 1 m.
m ³ or less, and the T
The SSG method requires an expensive noble metal crucible such as a platinum crucible, has a low growth rate, and has a very high manufacturing cost.

[0004] By improving the above problems, a larger Ba
Methods for easily and efficiently producing TiO ₃ single crystals have been studied.

For example, there have been attempts to efficiently produce BaTiO ₃ single crystals by a sintering method. JP 4
JP-A-300296, JP-A-5-155696 and JP-A-5-155797 disclose BaTiO _3.
A single crystal of BaTiO ₃ is joined as a seed crystal to the polycrystal of No. _{1, and} a method for producing a single crystal of BaTiO _{3 in} which the polycrystal is single-crystallized by a solid-phase reaction by heating the single crystal is disclosed. Japanese Patent Application Laid-Open No. 9-263496 discloses a BaTiO ₃ single crystal in which a BaTiO ₃ microcrystal particle aggregate having a Ti / Ba molar ratio of 1.0 or more and 1.1 or less is given a temperature gradient to form a single crystal. Is disclosed.

However, these methods have a large variation in single crystal growth rate, and cannot grow a large single crystal with good reproducibility. In addition, the dislocation density was high, and the crystallinity of the BaTiO ₃ single crystal was inferior to the conventional TSSG method or flux method.

Further, examples of a solid-phase method other than the sintering method can be seen. JP-A-59-3091 discloses PbTiO ₃ ,
There is disclosed a method for producing an oxide single crystal in which a crystalline oxide such as BaTiO ₃ , SrTiO ₃ , or CaTiO ₃ is melted, rapidly solidified and then amorphized, and then recrystallized under a temperature gradient. This method requires a step of melting the crystalline oxide, which complicates the manufacturing apparatus and manufacturing steps. In addition, the crystallinity of the obtained single crystal was poor, and only a crystal having a high pore content was obtained.

Further, regarding the TSSG method and the flux method
Improvements are also being considered. JP-A-6-321698
In the gazette, the flux method uses BaF_Two , NaF,
Li _Two MoO_Four Use a mixture such as
BaTiO_Three Is disclosed. By this
And BaTiO to the solution_Three Increase the solubility of
BaTiO of large size by crystal growth_Three Single crystal
It is intended to obtain
The strike was not satisfactory enough. JP
No. 9-59096 discloses that trace amounts of Mg and Fe are doped.
-Pressed BaTiO_Three A single crystal is disclosed. this is
The aim is to obtain high photorefractive properties in the near infrared region
However, it has an adverse effect on the piezoelectric properties of Mg, Fe, etc.
Effect element is contained, and it is preferable as a piezoelectric material.
It was not something. At the industrial level, production time and
It was not at a satisfactory level in terms of manufacturing costs.

[0009]

As described above, the TS
According to the method of manufacturing a BaTiO ₃ single crystal by the SG method, the flux method, or the like, it has been extremely difficult to significantly reduce the problems of manufacturing efficiency such as manufacturing time and manufacturing cost.
Further, in the method of manufacturing a BaTiO ₃ single crystal by the sintering method, improvement of the manufacturing efficiency was expected.
A sufficient effect could not be obtained due to variation in the growth rate of the O ₃ single crystal, and at the same time, the crystallinity of the obtained BaTiO ₃ single crystal was inferior to those of the TSSG method, the flux method and the like. That is, BaTiO ₃ having excellent crystallinity and physical properties
It has been difficult to produce a system single crystal in a short time and at low cost in the flow of the conventional technology.

In addition, PZT (Pb
(Ti, Zr) O_Three ) Polycrystalline is commonly used
However, in recent years, industrial products have been
It is required to reduce the amount of lead used in
In addition, a promising alternative to PZT to reduce lead usage
And BaTiO_Three Polycrystalline, Bi_0.5 Na_0.5 TiO
_ThreePolycrystalline, (Na_0.5 K_0.5 ) NbO_Three Think polycrystalline
Have been. However, PZT has a piezoelectric constant d₃₃=
300-400 (× 10^-12 C / N), electromechanical coupling
Number k₃₃= 0.6 to 0.7, whereas BaTiO
_Three Polycrystal has a piezoelectric constant d₃₃= 120 (× 10^-12 C /
N), electromechanical coupling coefficient k₃₃= 0.4-0.5,
Bi_0.5 Na_0.5 TiO_Three Polycrystal has a piezoelectric constant d₃₃= 1
10 (× 10^{-1 Two} C / N), electromechanical coupling coefficient k₃₃=
0.4 to 0.6, which is satisfactory for its piezoelectric characteristics.
It was not something that could be done. In addition, BaTiO_Three A single crystal is
Piezoelectric constant d ₃₃= 500 (× 10^-12 C / N), electric machine
Coupling coefficient k₃₃= 0.8 to 0.9, but Curie temperature
(T_c ) Is about 120 ° C. and BaTiO_Three Same as polycrystal
As low Curie temperature (T_c Usable temperature range accompanying)
Has been a practical difficulty in the past. Therefore, lead
-Free or low-lead material with excellent piezoelectric properties
Is being developed.

The inventors of the present invention have proposed a BaTiO_Three 
In the production of a single crystal, BaTiO _Three Add other ingredients to itself
Improved crystal reproducibility and crystallinity
And try to balance the improvement of other physical properties.
As a result of extensive investigation, BaTiO_Three PbTiO_Three Add
Only those systems that meet certain conditions
Found that crystal growth was caused with good reproducibility.
TiO_Three -PbTiO _Three A more detailed examination of the system
As a result, the present invention has been completed.

That is, the present invention provides a BaTiO ₃ -PbTiO ₃ single crystal having improved dielectric loss, electromechanical coupling coefficient, and excellent physical properties such as dielectric properties, piezoelectric properties, and pyroelectric properties. there is provided a BaTiO ₃ -PbTiO ₃ system single crystal as low piezoelectric material excellent of lead content in sex.

The BaTiO ₃ -PbTiO ₃ single crystal can be produced by a method other than the present invention described later, for example, a melt solidification method such as a flux method or a TSSG method.
It is considered more difficult than a BaTiO ₃ single crystal, and no value can be found in such a method. As described above, for the BaTiO ₃ single crystal, only a small size of about 1 mm ³ or less can be obtained by the flux method. In addition, the TSSG method requires an expensive noble metal crucible such as a platinum crucible, and the growing speed is low. 0.1-0.2m
Since it is on the order of m / h, there are disadvantages that the production cost is extremely high, the raw material loss is large, and it is difficult to obtain a large single crystal. As described above, it is inevitable that the cost is extremely high, and the field of use is extremely limited, and it is pointed out that the material lacks value as an industrial material. In terms of performance, impurities are likely to be mixed during the growth of the single crystal, and the original performance cannot often be exhibited. BaTiO ₃ -Pb
Similar problems are expected for TiO ₃ single crystals according to the melt solidification method.

An example of a method for producing a perovskite oxide single crystal by a sintering method is disclosed in Japanese Patent Application Laid-Open No. 9-18859.
No. 7, Pb @ (Mg _1/3 Nb _2/3 ) _1-x T
i _x ｝ O ₃ perovskite sintered body (0 ≦ x ≦ 0.55 in the above composition formula; 10 mol% or less of Pb may be replaced by Ba, Sr, Ca, etc.) 1000 ~ in lead atmosphere in closed container by contact with crystal
A method for producing a perovskite oxide single crystal comprising a step of heating at a temperature of 1450 ° C. is disclosed. However, there is no disclosure of the molar number of Pb is about less BaTiO ₃ -PbTiO ₃ system single crystal than the molar number of Ba, of course, it by effect not described. Further, the A-site and B-site of the perovskite sintered body
The point that the crystallization rate is extremely slow when the ratio of sites is 1.00> A / B has a tendency different from that of the present invention as described later.

An object of the present invention is to provide a BaTiO ₃ -PbTiO ₃ single crystal having improved dielectric loss and electromechanical coupling coefficient and excellent in various physical properties such as dielectric property, piezoelectric property and pyroelectric property. , BaTiO ₃ -PbTiO ₃ as a piezoelectric material having excellent piezoelectric properties and productivity and a low lead content
It is an object to provide a system single crystal.

Further, the present invention provides a simple bonding method by a melt solidification method.
Instead of crystal growth, BaTiO_Three -PbTiO_Three Single crystal
That can be efficiently produced_Three -PbT
iO _Three To provide a method for producing a system single crystal
And BaTiO_Three -PbTiO_Three Simple connection
Actuator and Liquid Discharge Head Using Crystal
The purpose is to provide.

[0017]

SUMMARY OF THE INVENTION As described above, the present inventors have found that BaTiO ₃ itself has been used in the production of BaTiO ₃ single crystals by a sintering method, which has not been able to grow single crystals with good reproducibility. By adding other components, we tried to achieve both improvement of single crystal growth reproducibility and improvement of crystallinity and other physical properties.
It found that those that meet certain conditions in a system plus PbTiO ₃ to BaTiO ₃ causes a very good reproducibility crystal growth has been led to completion of the present invention.

That is, the BaTiO ₃ -PbT of the present invention
The iO ₃ -based single crystal is single-crystallized by heating a BaTiO ₃ -PbTiO ₃ -based green compact or sintered body in which the mole number of Pb is smaller than the mole number of Ba while keeping it in a non-molten state. It is characterized by having. Thus, Pb
PbTiO ₃ is added to BaTiO ₃ so that the number of moles of BaTiO ₃ − is smaller than the number of moles of Ba.
By heating the PbTiO ₃ -based green compact or sintered body while keeping it in a non-molten state to form a single crystal, a stable single crystal can be grown.

In the BaTiO ₃ -PbTiO ₃ single crystal of the present invention, the dislocation density is 10 ² / cm ² or more and 10 ⁶ or more.
/ Cm ² or less, and the pore content is preferably in the range of 1 to 5% by volume. Thus, the BaTiO ₃ —PbTiO ₃ single crystal of the present invention
The dielectric loss is small and the electromechanical coupling coefficient is large. For example, the dielectric loss is 1% or less, and the electromechanical coupling coefficient exceeds 85%.

BaTiO of the present invention_Three -PbTiO_Three Simple connection
In the crystal, BaTiO_Three -PbTiO_Three To single crystal
PbTiO_Three Content of 45 mol% or less
Is preferred. BaTiO as starting material_Three -PbTi
O_Three PbTiO in system compact or sintered body_Three Containing
Rate of 45 mol% or less, the growth rate of the single crystal
Single crystal material is more stable and more stable
Can be manufactured. The resulting BaTiO
_Three -PbTiO_Three PbTiO in system-based single crystals _Three Containing
The rate is determined by the PbTiO_Three The same as the content of
is there. Furthermore, the BaTiO of the present invention_Three-PbTiO_Three system
PbTiO in single crystal_Three Is more preferable.
Is 30 mol% or less, more preferably 25 mol%.
It is as follows. PbTiO_Three If the content of Pb is too large, Pb
Evaporation becomes remarkable, and the composition fluctuates from the target composition.
The resulting single crystal tends to be porous. This Pb evaporation
The use of pressure vessels is indispensable to control
With the drawback that leads to the stop-up. In addition, Ba of the present invention
TiO_Three -PbTiO_Three PbTiO in system-based single crystals_Three 
Is more preferably 0.01 mol%
Or more, more preferably 0.02 mol% or more.
You.

The BaTiO ₃ -PbTiO ₃ single crystal of the present invention preferably has a volume of 1 mm ³ or more.
The BaTiO ₃ -PbTiO ₃ -based single crystal of the present invention can be easily increased to a volume of 1 mm ³ or more by stable crystal growth, and the single crystal has a volume of 1 mm ³ or more, thereby increasing the area. This makes it possible to cope with devices of various sizes, which is preferable.

In another embodiment of the present invention, the dislocation density is 1
0^Two Pieces / cm^Two More than 10⁶ Pieces / cm ^Two Below, the pore content
Is in the range of 1% by volume to 5% by volume.
BaTiO_Three -PbTiO_Three It is a system single crystal.
More preferably, PbTiO _Three Content of 45 mol% or less
Below. Thereby, the BaTiO of the present invention is obtained._Three -PbT
iO_Three Based single crystals have low dielectric loss and
It will be a large number.

Further, the BaTiO ₃ -PbTi of the present invention
O ₃ type method for producing a single crystal, 0.98 elemental molar ratio of the molar number of Pb contains less BaTiO ₃ -PbTiO ₃ system powder compact or sintered than the molar number of Ba
In the range of 00 <(Ba + Pb) / Ti <1.0000, the method includes a step of heating the green compact or the sintered body in a non-molten state to form a single crystal. More preferably, the molar ratio of the elements contained in the green compact or the sintered body is 0.9900 <(Ba + Pb) /
Ti <1.0000, more preferably 0.1 Ti.
9950 ≦ (Ba + Pb) /Ti≦0.9999. By heating thus remains containing the number of moles of Pb was kept unmelted less BaTiO ₃ -PbTiO ₃ system powder compact or sintered than the molar number of Ba, BaTiO ₃ containing no PbTiO ₃ The reproducibility of single crystal growth is improved and a stable BaTiO ₃ -Pb
Production of a TiO ₃ -based single crystal becomes possible. Further, B
By the ATiO ₃ -PbTiO ₃ system powder, or the molar ratio of the content to elements of the sintered body in a predetermined range, B
the crystal growth rate of aTiO ₃ -PbTiO ₃ system single crystal becomes faster.

In the method for producing a BaTiO ₃ —PbTiO ₃ single crystal according to the present invention, the BaTiO ₃ —PbTiO ₃
It is preferable that the content of PbTiO ₃ in the system compact or the sintered body is 45 mol% or less. By setting the content of PbTiO ₃ in the BaTiO ₃ —PbTiO ₃ based green compact or the sintered body as the starting material to 45 mol% or less, the growth rate of the single crystal is further promoted,
A single crystal substance can be more stably manufactured. In the method for producing BaTiO ₃ -PbTiO ₃ system single crystal of the present invention, the content of PbTiO ₃ in BaTiO ₃ -PbTiO ₃ system powder compact or the sintered body, more preferably 30 mol% or less, further Preferably 25
Mol% or less. If the content of PbTiO ₃ is too large, the evaporation of Pb becomes remarkable, and the single crystal obtained with composition fluctuation from the target composition tends to become porous. The use of a pressure vessel is indispensable for suppressing this Pb evaporation, and involves a drawback that leads to an increase in manufacturing cost. further,
In the manufacturing method of the BaTiO ₃ -PbTiO ₃ system single crystal of the present _invention, the minimum content of PbTiO ₃ in BaTiO 3 -PbTiO ₃ system powder compact or sintered, more preferably 0.01 mol% or more And more preferably 0.02 mol% or more.

The BaTiO of the present invention_Three -PbTiO
_Three The method for producing a system single crystal is preferably BaTiO_Three −
PbTiO_Three Temperature of the green compact or sintered body at 1200 ° C or higher1
Single crystallization by heating at a temperature below 400 ° C
The step of performing BaTiO _Three -PbTiO_Three System compact
Alternatively, the sintered body is heated in a predetermined temperature range as described above.
BaTiO_Three -PbTiO_Three Bonding of single crystal
The crystal growth rate increases.

The method for producing a BaTiO ₃ -PbTiO ₃ single crystal of the present invention preferably comprises the step of heating the green compact or sintered body in a lead atmosphere while keeping it in a non-molten state to form a single crystal. Including. One way to form lead atmosphere, in an environment of heating the BaTiO ₃ -PbTiO ₃ system powder, or sintered in a non-molten state, coexist lead-containing compounds, from the lead-containing compound A method of evaporating lead or lead oxide may be used. Ba
By heating the TiO ₃ -PbTiO ₃ system powder, or sintered in a lead atmosphere, BaTiO ₃ -PbTi
O ₃ based green compact or sintered or BaTiO ₃ -P,
Evaporation of lead or lead oxide from the bTiO ₃ -based single crystal can be prevented. Thereby, BaTiO ₃ -Pb
It is possible to suppress an increase in the dislocation density and the pore content of the TiO ₃ -based single crystal, and to produce a high-quality BaTiO ₃ -PbTiO ₃ -based single crystal.

Further, the BaTiO of the present invention_Three -PbTi
O_Three The method for producing a system single crystal is BaTiO_Three There is a system single crystal
Or BaTiO_Three -PbTiO_Three System single crystal as seed crystal
And composed of crystal grains having an average particle size of 20 μm or less.
BaTiO having a density of 95% or more_Three -PbTiO_Three Series
The consolidation is performed using the {100} plane, the {110} plane, or
Join with {111} surface and heat while keeping it in a non-molten state
Is characterized by being single-crystallized. And
More preferably, the BaTiO_Three -PbTiO _Three System pressure
The molar ratio of elements contained in the powder or sintered body is 0.995
0 ≦ (Ba + Pb) /Ti≦0.9999
Things. BaTiO of the present invention_Three -PbTiO_Three System simple
In the method for producing a crystal, BaTiO_Three −
PbTiO _Three Bonding the seed crystal with the green compact or sintered body
By using, the green compact or the seed crystal of the sintered body and
Single crystallization occurs stably from the junction of
Reproducibility is improved. Further, the green compact or the sintered body
If the molar ratio of the contained elements is within a predetermined range, BaTi
O_Three -PbTiO_Three Faster growth rate of single crystal
Become.

Further, a piezoelectric actuator according to the present invention includes the above-mentioned layer made of a BaTiO ₃ -PbTiO ₃ single crystal, and a liquid discharge head according to the present invention includes the piezoelectric actuator. It is characterized by.

The piezoelectric actuator and the liquid discharge head of the present invention are made of a BaT having a high electromechanical coupling coefficient, a high piezoelectric constant, and a high Curie temperature as a piezoelectric material.
iO ₃ -PbTiO ₃ system by using a single crystal, high-power, broad piezoelectric actuator of usable temperature region - is obtained by allowing the realization of data and the liquid ejection head further lead content is also less environmentally It is preferable from the viewpoint of improvement.

The present inventors have studied the Ba obtained by the present invention.
Was measured with respect to crystalline TiO ₃ -PbTiO ₃ system single crystal, further, BaTiO ₃ -PbTiO ₃ of the present invention
Dielectric system single crystal, piezoelectric, etc. pyroelectric, was investigated for the other physical properties, BaTiO ₃ -P of the present invention
The bTiO ₃ single crystal was found to be extremely excellent in crystallinity by measuring the crystallinity.
From X-ray diffraction and electron diffraction, it was confirmed that the crystal was a single crystal in which the crystal orientations were completely matched. In addition, from the low dislocation density observed by etch pit observation described later, it was confirmed that the crystal was a good quality crystal with few lattice defects, and the pore content was very low.

The BaTiO ₃ —PbTi of the present invention
Regarding the physical properties of the O ₃ -based single crystal, particularly excellent properties in piezoelectricity were found. It is not only the BaTiO ₃ polycrystal but also the PZT
It surpassed the characteristics of the (Pb (Ti, Zr) O ₃ ) polycrystal and the BaTiO ₃ single crystal produced by the TSSG method. The BaTiO ₃ -PbTiO ₃ system single crystal of the present invention,
Considering from the viewpoint of the piezoelectric material, the advantages of achieving a wide usable temperature range and a low lead content at the same time as excellent piezoelectric characteristics can be cited.
In recent years, in order to reduce the burden on the global environment, the use of lead in industrial products has been required to be reduced in recent years. For the BaTiO ₃ —PbTiO ₃ single crystal of the present invention, the mainstream of piezoelectric materials is currently Compared with the PZT polycrystal, the amount of lead used can be greatly reduced due to the difference in composition, and the piezoelectric properties are significantly improved, so that the piezoelectric material required to produce the same effect is obtained. The amount of used itself can be greatly reduced.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS BaTiO ₃ -PbTi of the present invention
The O ₃ -based single crystal is single-crystallized by heating a BaTiO ₃ -PbTiO ₃ -based green compact or a sintered body in which the mole number of Pb is smaller than the mole number of Ba while keeping it in a non-molten state. It is something. Furthermore, the BaTi of the present invention
The O ₃ —PbTiO ₃ -based single crystal is made of the BaTiO ₃ —P
The molar ratio of the elements contained in the bTiO ₃ -based green compact or sintered body is set to 0.9800 <(Ba + Pb) / Ti <1.000
It is preferable to set the range to 0 so that the green compact or the sintered body is heated while keeping it in a non-molten state to form a single crystal. More preferably, the molar ratio of the elements contained in the green compact or the sintered body is 0.9900 <(Ba + Pb) / T
i <1.0000, more preferably 0.9
950 ≦ (Ba + Pb) /Ti≦0.9999.

The effect of improving the reproducibility of crystal growth in the BaTiO ₃ -PbTiO ₃ single crystal of the present invention is as follows.
Even if the production method of the present invention is applied to a green compact or a sintered body having a composition of only O _3, no expression occurs. The mechanism has not been confirmed, but is presumed as follows. BaT
When heated while maintaining iO ₃ -PbTiO ₃ system powder compact or sintered in a non-molten state, in the green compact or the surface of the sintered body of lead or a lead compound to diffuse to the outside and evaporated. Due to lack of lead on the surface of the compact or sintered body,
In order to compensate for this, the movement of lead from the inside of the compact or the sintered body to the surface occurs. At this time, it is considered that the crystal grain boundaries inside the green compact or the sintered body easily move, and stable crystal growth occurs.

BaTiO of the present invention_Three -PbTiO_Three System simple
The crystals are BaTiO, the starting material. _Three -PbTiO_Three system
Compacted or sintered PbTiO_Three Content of 45 mol
% Is preferable. The green compact or the sintered body
PbTiO_Three Content of 45 mol% or less
The single crystal growth rate is further promoted, and
A single crystal material can be manufactured more stably. The result
BaTiO obtained _Three -PbTiO_Three Composition of single crystal
Is the starting material BaTiO_Three -PbTiO_ThreeSystem compact
Alternatively, the composition becomes almost the same as the composition of the sintered body. More preferred P
bTiO_Three Is 30 mol% or less, and
Preferably it is 25 mol% or less. In addition, PbTiO_Three 
If the content of_Three -PbTiO_Three system
Evaporation of lead from green compacts, sintered compacts or single crystals is remarkable.
You. The resulting BaTiO_Three -PbTiO
_Three Deviation from the target composition due to fluctuations in the composition of the base single crystal
Is generated. Further obtained BaTiO_Three -PbTiO_Three 
The system single crystal tends to be porous. Evaporation of this lead
The use of pressure vessels is indispensable to control
With the drawback that leads to the stop-up. In addition, the BaTi
O_Three -PbTiO_ThreePb in green compact or sintered body
TiO_Three As the minimum content of
1 mol% or more, more preferably 0.02 mol%
That is all.

The BaTiO ₃ -PbTiO of the present invention
_{The 3-} series single crystal is single-crystallized by heating a BaTiO ₃ -PbTiO ₃ -based green compact or sintered body, preferably in a temperature range of 1200 ° C. or more and 1400 ° C. or less. By heating in a predetermined temperature range in this manner, it is possible to produce a crystal at a high crystal growth rate.

The BaTiO ₃ -PbTiO of the present invention
_{The 3} system single crystal is a BaTiO ₃ system single crystal or BaTi
Another single crystal such as an O ₃ -PbTiO ₃ -based single crystal is used as a seed crystal, and the seed crystal is joined to a BaTiO ₃ -PbTiO ₃ -based compact or sintered body, and further stabilized by heating and holding the seed crystal. (Note that it is premised that the polycrystal and the seed crystal have the same crystal structure, and that both the lattice constant and the thermal expansion coefficient of the polycrystal and the seed crystal are different. It is preferably within ± 15%). 1A to 1D show BaTiO ₃ -Pb.
By bonding a predetermined single crystal 1 as a seed crystal to a TiO ₃ -based green compact or sintered body 3 and heating it in a non-molten state,
Shows the state of crystal growth when the production of BaTiO ₃ -PbTiO ₃ system single crystal of the present invention. As shown in FIG. 1B, it can be seen that crystal growth occurs remarkably in the joint portion between the BaTiO ₃ -PbTiO ₃ green compact or the sintered body 3 and the seed crystal 1, particularly in the peripheral region. . This is considered to be because lead movement particularly occurred in the peripheral region, and is considered to be a phenomenon supporting the above-described crystal growth mechanism. Typically, in FIG. 1C, reference numeral 5 indicates a single crystallized portion, and reference numeral 7 indicates a polycrystalline portion.

When the seed crystal is used as described above, BaTi
O_Three -PbTiO_Three Seeds in which the crystal orientations of a single crystal are bonded
Crystal orientation can be matched. Furthermore, the present invention
BaTiO_Three -PbTiO_Three The system single crystal is BaTiO_Three 
System single crystal or BaTiO _Three -PbTiO_Three Single crystal
Is a seed crystal and is composed of crystal grains with an average particle size of 20 μm or less.
BaTiO having a relative density of 95% or more_Three -PbT
iO_Three The system-based sintered body was formed by {100} plane of the seed crystal, {11}
Joined with {0} plane or {111} plane and kept in non-molten state
Single crystallization may be performed by heating while maintaining the temperature. here
BaTiO used as seed crystal_Three System single crystal or
BaTiO_Three -PbTiO_Three The system single crystal is Ba of the present invention.
TiO_Three -PbTiO_Three Manufactured by the method of manufacturing
Or by a general sintering method
Can be used, or flux or TSSG methods
May be used. The reason is clear
However, the BaTiO of the present invention_Three -PbTiO_Three system
Using a single crystal produced by a single crystal manufacturing method as a seed crystal
If it is, it is manufactured by flux method or TSSG method.
BaTiO with better quality than using a single crystal
_Three -PbTiO_Three A system single crystal can be produced.

The method for producing a BaTiO ₃ -PbTiO ₃ system single crystal of the present _invention, a BaTiO 3 -PbTiO ₃ system powder, or sintered, preferably heated while keeping the unmelted in lead atmosphere single It includes a step of crystallization. One of the methods for forming a lead atmosphere is B
in an environment of heating the ATiO ₃ -PbTiO ₃ system green compact or sintered body, a method, for example, PZT, coexist lead-containing compounds such as PbTiO _3, evaporation of the lead or lead oxide from the lead-containing compound . Thus, it is possible to suppress the BaTiO ₃ -PbTiO ₃ system composition fluctuation of the single crystal during growth (especially the evaporation of lead from BaTiO ₃ -PbTiO ₃ system single crystal) can be further increased crystallization rate.

However, when the content of PbTiO ₃ is 3
If making more than 0 mol% BaTiO ₃ -PbTiO ₃ system single crystal, in particular evaporation of lead becomes remarkable, easily occurs a composition change from target composition. Further, the pore content of the obtained single crystal tends to increase. In order to suppress the evaporation of lead, it is often not enough to perform the heating step in a lead atmosphere as described above. For example, it is preferable to perform a heating step under a pressure exceeding 1 atm in a pressure vessel. HI
Single crystal synthesis by a sintering method using a pressure vessel such as P requires a relatively long heat treatment time (10 hours or more), which is disadvantageous in terms of productivity and cost as compared with that under normal pressure.
BaTiO ₃ -PbTiO ₃ system single crystal of the present invention, dislocation density is 10 ² / cm ² or more 10 ⁶ / cm ² or less, it is desirable pore content is 5 vol% or more 1 ppm by volume . Thereby, the single crystal of the present invention has a small dielectric loss and a large electromechanical coupling coefficient.
For example, the dielectric loss is 1% or less, and the electromechanical coupling coefficient exceeds 85%.

The BaTiO ₃ -PbTiO of the present invention
It is desirable that the _3- series single crystal has a volume of 1 mm ³ or more. By having a volume of 1 mm ³ or more, it is possible to cope with devices of various sizes by increasing the area.

In the manufacturing method of the present invention, BaTi
The raw material powder used for producing the O ₃ —PbTiO ₃ green compact or the sintered body is not particularly limited, and examples thereof include the following. When the solid-phase reaction is used, 1) BaTiO ₃ powder is prepared by calcining a mixed powder of BaO (obtained by thermal decomposition of BaCO ₃ or barium oxalate) and TiO _2, and PbO and TiO
PbTiO ₃ powder was prepared by calcination of a powder mixture with Pb ₂ and a mixture of these powders, and 2) Ba
Ba made directly from O, PbO and TiO ₂ powder
Such as TiO ₃ -PbTiO ₃ system powder.

Also, a wet method such as a coprecipitation method or an oxalic acid method, or a hydrothermal method
BaTiO obtained by the method_Three Powder or PbTiO_Three Powder
Or wet method such as coprecipitation method or oxalic acid method, or hydrothermal
BaTiO obtained by the method_Three -PbTiO_Three System powder
And so on. The raw material powder is
Preferably, the average particle size is in the range of 0.05 to 5 μm.
No. Also, as mentioned above,
BaTiO as starting material_Three -PbTiO_Three System
Or the molar ratio of the elements contained in the sintered body is 0.9800 <
Raw materials so that (Ba + Pb) / Ti <1.0000
It is preferable to prepare the powder. Also more preferred
Or BaTiO_Three -PbTiO_Three System compact or sintered body
Is 0.9900 <(Ba + P
b) Adjust raw material powder so that /Ti<1.0000
And more preferably 0.9950 ≦ (Ba
+ Pb) /Ti≦0.9999. composition
The adjusted powder is used in a uniaxial press or cold isostatic press.
A general compact is formed into a green compact. The resulting green compact
A sintered body may be obtained by sintering under ordinary conditions.
Heat these compacts or sintered bodies in a non-molten state.
And BaTiO _Three -PbTiO_Three System single crystal
A large crystal grain having an average particle size of 1 mm or more is obtained. Non-melting
Heating in the state is more preferably 1200 ° C. or more and 140 ° C.
It is performed in a temperature range of 0 ° C. or less. Further obtained in the manner described above
By using the obtained single crystal as a seed crystal,
BaTiO_Three -PbTiO_Three System-based single crystals relatively easily
It can also be made.

As mentioned above, the larger BaTiO ₃ −
In order to easily produce a PbTiO ₃ single crystal, it is preferable to use another single crystal as a seed crystal. Joining the BaTiO ₃ -PbTiO ₃ system green compact or sintered body and the seed crystal as a starting material, performing single crystallization by heating maintained. Preferred seed crystals include BaTiO ₃ -based single crystals and BaTiO ₃ -PbTiO ₃ -based single crystals. As a preferable method for producing a seed crystal, a method for producing a BaTiO ₃ —PbTiO ₃ single crystal of the present invention,
Examples include a general sintering method and a melt solidification method such as a TSSG method and a flux method. In particular, the use of single crystal by the production method of BaTiO ₃ -PbTiO ₃ system single crystal of the present invention as seed crystals, obtained BaTiO ₃
-PbTiO ₃ -based single crystal is preferable because it tends to suppress crystal defects. The seed crystal is cut out of a {100} plane, a {110} plane or a {111} plane, and polished to form a bonding surface.

In the case of performing single crystallization using a seed crystal, the molar ratio of elements contained in the BaTiO ₃ —PbTiO ₃ sintered body to be single crystallized is 0.9800 <(Ba + P
It is preferable to adjust so that b) / Ti <1.0000. More preferably, 0.9900 <(Ba + P
b) / Ti <1.0000, more preferably 0.9950 ≦ (Ba + Pb) / Ti ≦ 0.
9999. Further, the sintered body is sintered until the average grain size of the crystal grains becomes 20 μm or less and the relative density becomes 95% or more. Although the sintering method is not particularly limited, for example, normal pressure sintering, hot pressing, H
IP (hot isostatic pressing) and the like. If the porosity of the sintered body exceeds 5% by volume, the porosity in the single crystal obtained by crystal growth increases, and the mechanical strength decreases, which is not preferable. In particular, in a composition having a high lead content, the lead content tends to increase due to evaporation of the lead during the growth of the single crystal. Therefore, in this case, it is particularly preferable to keep the pore content of the sintered body at 5% by volume or less. The joining surface of the sintered body and the seed crystal has a surface roughness Ra = 1.
It is preferable to perform precision polishing to a thickness of 0 nm or less and a flatness λ (λ = 633 nm) or less. The polished surface of the sintered body may be in direct contact with the polished surface of the seed crystal, or an organic or inorganic acid containing Ba, Pb, or Ti, which does not become an impurity, is applied to the contact surface and then brought into contact. Is also good. Also,
It is preferable that the seed crystal and the sintered body, whose polishing surfaces are brought into contact with each other, are joined by heating for a predetermined time under their own weight or under a load of about 9.8 MPa or less. Furthermore, in order to suppress the evaporation of lead from near the sample surface in the joining step,
Preferably, the joining is performed in a lead atmosphere.

The BaTiO ₃ -PbTiO ₃ single crystal of the present invention may contain a small amount of an additive that cannot be substituted or is extremely difficult to be substituted at the A site or the B site of the perovskite ABO ₃ structure for the purpose of promoting the crystal growth. Alternatively, the A site or the B site of the perovskite ABO ₃ structure may be replaced with another element, or a third component of another perovskite structure may be dissolved for the purpose of site replacement. These amounts are not particularly limited, but preferred amounts are 10% by weight or less as a trace amount of an additive, and 10% by mole of each site as an element to replace the A site or the B site.
Hereinafter, the third component to be dissolved is 10 mol% of all components.
It is as follows. The type of these components is not particularly limited, but preferably, Na, K, Ca, Cr, C
o, Bi, Sr, La, Zr, Sn, Mg, Mn, Z
Examples include elements (ions) such as n, Nb, Ta, and Ni, and oxides and composite oxides containing these elements. In addition, the impurity component for promoting the crystal growth partially remains in the single crystal as an impurity as the crystal growth interface moves, but most of the components move to the end of the grown crystal. Not a problem.

The elemental analysis of Ba, Pb, Ti and the like in a green compact, a sintered body or a single crystal includes X-ray fluorescence analysis, ICP (emission plasma) analysis, and ICP-MASS.
Based on an analysis method such as (emission plasma-mass) analysis,
Each can be performed using a dedicated analyzer. Further, the crystallinity and orientation of the single crystal can be determined by observing an etch pit image used in the measurement of dislocation density described later, in-plane measurement of X-ray diffraction, and out-of-plane.
It can be confirmed by methods such as ne measurement and electron diffraction measurement.

When the value of the pore content in the sintered body and the grown single crystal is about 0.1% by volume or more, the amount of pores (pore area) exposed on the sample surface after mirror polishing is determined. It can be measured by a reflection microscope, SEM (scanning electron microscope) or the like, and can be calculated from the ratio to the measured area. Also, 0.1
In the case of less than about% by volume, this method lacks accuracy. Therefore, a thin piece having a thickness of about several tens of μm is prepared, the pore size and the number present in the observation field of the transmission microscope are measured, and the ratio is determined from the ratio to the observation volume. .

Dislocations in a single crystal can be observed using a microscope or the like as pits (etch pits = dislocations) by corroding the crystal face of the single crystal with a corrosive agent such as an HCl-HF solution. it can. Specifically, several 100 to 100
The dislocation density can be determined by counting the number of dislocations (etch pits) generated at 0 μm ² and converting this to 1 cm ² .

[0049]

The present invention will be described in more detail with reference to specific examples below, but the present invention is not limited to these examples.

Example 1 TiO ₂ (26.7557)
g), PbO (0.7440 g) and BaCO ₃ (6
5.1209 g) were wet-mixed, dried and dried at 1100 ° C. for 5 minutes.
This is calcined for a period of time, crushed and molded
m disk shape). In the green compact formed at this time, the molar ratio of the contained elements is (Ba + Pb) / Ti =
0.9950. This was sintered at 1360 ° C. for 10 hours to obtain a sintered body. This sintered body has an average particle size of about 2.
It is composed of coarse crystal grains of 0 mm, and the composition of the sintered body is 99.0 mol% BaTiO ₃ -1.0 mol% PbT
It has been a iO _3. Coarse crystal grains were taken out from the sintered body as seed crystals, and the (100) plane of the crystal grains was cut out to finish the surface roughness Ra = 0.2 nm and the flatness λ / 2. On the other hand, the same composition was formed into a disk shape having a diameter of 10 mm and a thickness of 15 mm, and sintered at 1280 ° C. for 3 hours to obtain 99.0 mol% BaTiO ₃ having a relative density of 97.3%.
A 0 mol% PbTiO ₃ sintered body was obtained. The average grain size of the crystal grains constituting this sintered body was about 10 μm, and the composition was (Ba + Pb) /Ti=0.9950. The end face of this sintered body was similarly subjected to surface roughness Ra = 0.2
After the mirror-finished surface with a nm and flatness of λ / 2, the above-mentioned polished surfaces of the seed crystal and the sintered body were washed with acetone, and then both were mechanically joined. While maintaining this state, 1
It was kept at 360 ° C. for 40 hours to perform single crystallization without melting. In growing the single crystal, the sample was covered with a magnesia crucible to suppress evaporation of Pb. After the growth treatment, the single crystal was formed from the surface bonded to the single crystal to about 12 mm.

From the results, the growth rate was 0.3 mm / h
It was found that the growth could be performed at a much higher speed than the growth speed of the conventional melt solidification method. Further, 99.0 mol% of BaTiO ₃ -1.0 obtained by a sintering method using a seed crystal.
The pore content of the mol% PbTiO ₃ single crystal is 0.9% by volume.
When the dislocation density was examined by etching in an HCl-HF solution, it was 1 × 10 ³ / cm ² .

(Example 2) TiO ₂ (26.6486)
g), PbO (5.2080 g) and BaCO ₃ (6
1.1742 g) was wet-mixed, dried and dried at 1150 ° C. for 5 minutes.
This is calcined for a period of time, pulverized and molded (diameter 20 m).
m disk shape). In the green compact formed at this time, the molar ratio of the contained elements is (Ba + Pb) / Ti =
0.9990. This was sintered at 1350 ° C. for 10 hours to obtain a sintered body. This sintered body has an average particle size of about 3.
It is composed of coarse crystal grains of 0 mm, and the composition of the sintered body is 93.0 mol% BaTiO ₃ -7.0 mol% PbT
It has been a iO _3. Coarse crystal grains were taken out from the sintered body as seed crystals, and the (110) plane of the crystal grains was cut out to finish the surface roughness Ra = 0.3 nm and the flatness λ / 4.

On the other hand, the same composition was prepared with a diameter of 10 mm and a thickness of 20 mm.
mm, and sintered at 1250 ° C. for 3 hours for 93.0 mol% BaTiO ₃ having a relative density of 99.1%.
A −7.0 mol% PbTiO ₃ sintered body was obtained. The average grain size of the crystal grains constituting the sintered body was about 8 μm. The molar ratio of the elements contained in this sintered body is (Ba + Pb) / Ti =
0.9990. The end face of the sintered body is mirror-finished to a surface roughness Ra of 0.2 nm and a flatness of λ / 2, and both polished surfaces of the seed crystal and the sintered body are washed with acetone,
A mixed solution of BaCl ₃ and TiOCl ₂ (solution having a mixing ratio of 1: 0.5) was applied to the bonding interface and bonded. While maintaining this state, it was kept at 1370 ° C. for 50 hours in an oxygen atmosphere to perform single crystallization without melting. After the growth treatment, a single crystal was formed from the surface bonded to the seed crystal to about 18 mm.

From these results, it was found that the growth rate was 0.36 mm /
h, which indicates that the growth can be performed at a much higher speed than the growth speed of the conventional melt solidification method. Further, 93.0 mol% of BaTiO ₃ -7.7 obtained by a sintering method using a seed crystal.
The pore content of the 0 mol% PbTiO ₃ single crystal was 0.8% by volume, and the dislocation density was determined by etching in an HCl-HF solution. The dislocation density was 5 × 10 ² / cm ² .

(Example 3) A commercially available BaTiO ₃ single crystal produced by the TSSG method was 5 × 5 ×
The surface was cut into 0.5 mm and this surface was subjected to surface roughness Ra = 0.4
and a flatness of λ / 6. On the other hand, BaTiO ₃ (Ba / Ti = 0.9996) powder prepared by a hydrothermal method and PbTiO ₃ (Pb / Ti = 1.000) prepared by a solid-phase method.
0) The powder was mixed at a ratio of 99.8 moles to 0.2 moles, pot-milled, molded (disc shape having a diameter of 16 mm), sintered at 1280 ° C for 3 hours, and subjected to a relative density of 98.9%. Was produced. 99.8 obtained
In the sintered body of mol% BaTiO3-0.2 mol% PbTiO3, the molar ratio of the contained elements is (Ba + Pb) / T
i = 0.9996. This 99.8 mol% B
The average grain size of the crystal grains constituting the aTiO ₃ -0.2 mol% PbTiO ₃ sintered body was about 12 μm. The end face of this sintered body is mirror-finished to a surface roughness Ra of 0.4 nm and a flatness of λ / 6, and both the polished surfaces of the seed crystal and the sintered body are washed with acetone and then mechanically joined to each other. I let it. While maintaining this state, it was kept at 1380 ° C. for 30 hours in an oxygen atmosphere to perform single crystallization without melting. After the growth treatment, a single crystal was formed from the surface bonded to the seed crystal to about 11 mm.

From this result, the growth rate was 0.37 mm /
h, which indicates that the growth can be performed at a much higher speed than the growth speed of the conventional melt solidification method. Further, 99.8 mol% of BaTiO ₃ -0.0.9 mol% obtained by a sintering method using seed crystals.
The pore content of the 2 mol% PbTiO ₃ single crystal was 0.7% by volume, and the dislocation density was determined by etching in an HCl-HF solution. As a result, it was 5 × 10 ³ / cm ² .

(Example 4) Sintering method under the same conditions as in Example 2
Was used to grow a single crystal. However, in this embodiment, 150
Molybdenum silicon with an effective volume of × 150 × 150mm
Using an electric furnace with side heating elements, and 30 samples in it
Insert 6 PZT sintered bodies with a diameter of 20mm, 100%
The growth was performed in an oxygen atmosphere. Sample length after processing
All were single-crystallized to around 18 mm. Approximate production speed
When calculating the degree, a sample with a diameter of 16 mm and a length of 18 mm
(Volume 3.6cm^Three ) Is completed, so 108
cm^Three/ Furnace. The time required for training is 50 hours
So 2.16cm per hour ^Three And productivity is extremely high
High.

Example 5 Calcination at 1150 ° C. for 5 hours
BaTiO of the solid-phase method obtained by pulverization _Three (B
a / Ti = 0.9973) Powder and Pb prepared by wet method
TiO_Three (Pb / Ti = 1.0000) powder to 75.0
Wet-mix at a ratio of 25.0 moles per mole and mold this
(Disc shape with a diameter of 30 mm). Molding at this time
In the compact, the molar ratio of the contained elements is (Ba + P
b) /Ti=0.9998. This is 132
Sintering was performed at 0 ° C. for 50 hours to obtain a sintered body. This sintered body is
It is composed of coarse crystal grains with a diameter of about 1.10 mm,
The composition of the sintered body is 75.0 mol% BaTiO_Three −25.0
Mol% PbTiO_Three It was. 7 from this sintered body
5.0 mol% BaTiO_Three -25.0 mol% PbTiO
_Three Coarse crystal grains (single crystals) were taken out.

75.0 thus obtained by the sintering method.
The porosity of the mol% BaTiO ₃ -25.0 mol% single crystal is 3.2% by volume, and the dislocation density is determined by etching in a HCl-HF solution to find 1 × 10 ² /
cm ² and had few crystal defects.

(Example 6) Fabricated by the same method as in Example 5.
BaTiO_Three (Ba / Ti = 0.9973) powder and
PbTiO_Three (Pb / Ti = 1.0000)
Wet-mix at a ratio of 5.0 moles to 25.0 moles,
It was molded (disc shape with a diameter of 20 mm). At this time
In the shaped green compact, the molar ratio of the contained elements is (Ba
+ Pb) /Ti=0.9998. This one
Sintered at 190 ° C. for 5 hours. The composition of this sintered body is 75.
0 mol% BaTiO_Three -25.0 mol% PbTiO_Three so
And the relative density was 97.8%. This sintered body
Was composed of crystal grains having an average particle size of about 10 μm. this
The end face of the sintered body was made to have a surface roughness Ra = 0.2 nm and a flatness λ /
6. Next, the melt solidification method used as a seed crystal
BaTiO by_Three Same accuracy for (100) end face of single crystal
Processed to. Contact the sintered body and the seed crystal on both polished surfaces
And apply a pressure of 9.8 MPa for 1 hour at 1200 ° C.
Joining was performed. 30.0 mol% B with the bonded sample
aTiO_Three -70.0 mol% PbTiO _Three Set the sintered body
And place it over a MgO crucible to form a lead atmosphere.
Then, single crystallization was performed at 1280 ° C. for 30 hours. Upbringing
After processing, a single crystal is about 14 mm from the surface joined with the seed crystal.
Had been transformed.

From the results, the growth rate was 0.47 mm /
h, and could be grown at a higher speed than the conventional melt-solidification method. 75.0 mol% BaTi obtained by sintering method
The porosity of the O ₃ -25.0 mol% PbTiO ₃ single crystal was 2.1% by volume, and the dislocation density was determined by etching in a HCl-HF solution to find that it was 5 × 10 ² / cm.
The crystal defect of ² was small.

Example 7 TiO ₂ (26.6753)
g), PbO (5.2080 g) and BaCO ₃ (6
1.1742 g), dried, calcined at 1150 ° C. for 5 hours, pulverized and molded (diameter 20
mm disk shape). The molar ratio of the elements contained in this compact was (Ba + Pb) /Ti=0.9980. This was sintered at 1350 ° C. for 10 hours. The obtained sintered body is composed of coarse crystal grains having an average particle size of about 3.0 mm, and the composition of the sintered body is 93.0 mol% BaTi
O ₃ -7.0 mol% PbTiO ₃ . Coarse crystal grains are taken out from the sintered body as seed crystals, and the (110) plane of the crystal grains is cut out to obtain a surface roughness Ra = 0.3n.
m and flatness λ / 4.

On the other hand, the same composition was prepared by mixing 10 mm in diameter × 20 mm in thickness.
mm, and sintered at 1250 ° C. for 3 hours for 93.0 mol% BaTiO ₃ having a relative density of 99.1%.
-7.0 was obtained mole% PbTiO _3. The average grain size of the crystal grains constituting the sintered body is about 7 μm, and the molar ratio of the elements contained in the sintered body is (Ba + Pb) / Ti = 0.
9980. The end face of this sintered body is defined as a surface roughness R
a = 0.2 nm, mirror-finished to a flatness of λ / 2, and both the polished surfaces of the seed crystal and the sintered body are washed with acetone,
A mixed solution of BaCl ₃ and TiOCl ₂ (solution having a mixing ratio of 1: 0.5) was applied to the bonding interface and bonded. Sample and PZT
One sintered body was placed on a setter, and an atmosphere containing Pb was formed by further covering the MgO crucible. While maintaining this state, hold at 1370 ° C. for 20 hours,
Single crystallization was performed without melting. After the growing treatment, the single crystal was formed from the surface bonded to the single crystal to about 18 mm.

From the results, it was found that the growth rate was 0.90 mm /
h, which indicates that growth can be performed at a higher speed than that shown in Example 2. In addition, 9 obtained by the sintering method
3.0 mol% BaTiO ₃ -7.0 mol% PbTiO ₃
In the single crystal, it was confirmed that the Pb concentration in the surface layer portion of the sample was hardly different from the Pb concentration in the central portion, and that the entire sample had a uniform composition. 93.0 mol% BaTiO produced
₃ -7.0 porosity content of mol% PbTiO ₃ single crystal is 0.4% by volume, also was examined by etching dislocation density HCl-HF solution, 5 × 10 ² / cm ²
Met.

(Embodiment 8) The TSSG method was performed in the same manner as in Embodiment 3.
BaTiO manufactured by_Three Single crystal orientation (111)
Cut out 5 x 5 x 0.5 mm on the surface, this surface is the surface roughness
Ra = 0.3nm, flatness λ / 4 to make seed crystal
Was. On the other hand, BaTiO manufactured by the oxalate method _Three (Ba / T
i = 0.9993) Powder and PbTiO prepared by solid phase method
_Three (Pb / Ti = 0.9960) 93.2 moles of powder
Mix at 6.8 mol ratio and pulverize in a pot mill
This was molded (disk shape of 16 mm in diameter) and 12
Hot press sintering at 00 ° C for 1 hour and relative density of 99.4
% Sintered body was produced. The composition of the obtained sintered body was 93.
2 mol% BaTiO_Three -6.8 mol% PbTiO_Three In
Was. The molar ratio of the elements contained in the sintered body is (Ba + Pb)
/Ti=0.9991, and the sintered body is an average particle
It was composed of crystal grains having a diameter of about 2 μm. The end face of the sintered body
Mirror finish to surface roughness Ra = 0.3nm, flatness λ / 4
Then, both the polished surfaces of the seed crystal and the sintered body are washed with acetone.
After that, the two were mechanically joined. Bonded sample and PZ
Place one T sintered body on the setter, and further
An atmosphere containing Pb was formed by covering the pot.
While maintaining this state, 2370 at 1370 ° C. in an oxygen atmosphere
By holding for 0 hour, single crystallization was performed without melting. Upbringing
After processing, a single crystal is about 14 mm from the surface joined with the seed crystal.
Had been transformed.

From the results, it was found that the growth rate was 0.70 mm /
h, which indicates that the growth can be performed at a much higher speed than the growth speed of the conventional melt solidification method. Further, 93.2 mol% of BaTiO ₃ −6. Obtained by a sintering method using a seed crystal.
The pore content of the 8 mol% PbTiO ₃ single crystal was 0.2% by volume, and the dislocation density was determined by etching in an HCl-HF solution to find that it was 1 × 10 ³ / cm ² .

(Embodiment 9) As in Embodiment 3, the TSSG method
BaTiO manufactured by_Three Single crystal orientation (100)
Cut out 5 x 5 x 0.5 mm on the surface, this surface is the surface roughness
Ra = 0.3nm, flatness λ / 4 to make seed crystal
Was. On the other hand, BaTiO manufactured by the oxalate method _Three (Ba / T
i = 0.9990) Powder and PbTiO prepared by solid phase method
_Three (Pb / Ti = 0.9980) 90.7 mol of powder
Mixing at a ratio of 9.3 mol to pot mill grinding
This is molded (disk shape of 16 mm in diameter)
O for 1 hour at 200 ° C^Two -HIP (atmosphere is 20% O^Two ,
Pressure 98MPa) Sintered 9 with relative density of 99.96%
0.7 mol% BaTiO_Three -9.3 mol% PbTiO_Three
A sintered body was produced. The obtained sintered body has an average particle size of about 1 μm.
Was formed. Elements contained in this sintered body
Is (Ba + Pb) /Ti=0.9989.
I was The end face of the sintered body was made to have a surface roughness Ra = 0.3 nm,
Mirror finish to a flatness of λ / 4, both seed crystal and sintered body
After washing the polished surface with acetone, the two are mechanically joined.
Was. One piece each of the joined sample and PZT sintered body on the setter
And Pb by covering with MgO crucible
Atmosphere was formed. While maintaining this state,
Hold at 1370 ° C for 19 hours in an atmosphere, and simply
Crystallization was performed. After the growth process, from the surface joined with the seed crystal
Single crystallization had occurred up to about 18 mm.

From the results, it was found that the growing speed was 0.95 mm /
h, which indicates that the growth can be performed at a much higher speed than the growth speed of the conventional melt solidification method. Further, the porosity content of BaTiO ₃ -PbTiO ₃ single crystal obtained by sintering method using a seed crystal was 0.0003 vol%, the sample HC
When the dislocation density was examined by etching in a 1-HF solution, it was 1 × 10 ³ / cm ² .

(Embodiment 10) As in Embodiment 3, TSSG
The commercially available BaTiO ₃ single crystal produced by the
0) The surface was cut into 5 × 5 × 0.5 mm, and this surface was polished to a surface roughness Ra = 0.3 nm and flatness λ / 4 to obtain a seed crystal. On the other hand, BaTiO ₃ (Ba
/Ti=0.9945) Powder and PbT prepared by solid phase method
55.0 powder of iO ₃ (Pb / Ti = 0.9952)
By molding it together with a mixing ratio of the mole-to 45.0 moles pot grinding (disc shape with a diameter of 16 mm), 1 hour at 1200 ℃ O ² -HIP (atmosphere 20%
O ² , pressure 98MPa) sintered and relative density 99.96%
55.0 mol% of BaTiO ₃ -45.0 mol% of PbT
An iO ₃ sintered body was produced. The obtained sintered body was composed of crystal grains having an average particle size of about 3 μm. The molar ratio of the elements contained in this sintered body is (Ba + Pb) /Ti=0.9948
It was. The end face of the sintered body is made to have a surface roughness Ra = 0.3n.
After the mirror surface was finished to a m and a flatness of λ / 4, the polished surfaces of the seed crystal and the sintered body were washed with acetone, and then both were mechanically joined. Each of the bonded sample and the PZT sintered body was placed on a setter and further covered with an MgO crucible to form an atmosphere containing Pb. While maintaining this state, the substrate was kept at 1360 ° C. for 20 hours in an oxygen atmosphere to perform single crystallization without melting. After the growth treatment, single crystal was formed from the surface bonded to the seed crystal to about 13 mm, but the formed single crystal had a pore content of 8.9% by volume and was not in a porous and usable state.

Based on the results, the growth atmosphere was changed to 20% O ²
The joint sample of the seed crystal and the sintered body was held at 1350 ° C. for 24 hours at a pressure of 50 atm with a composition of −80% Ar, and heat treatment was performed without melting. After the treatment under pressure, the sample was monocrystallized up to about 15 mm from the surface joined with the seed crystal, and the growth rate was 0.63 mm / h, which is much higher than the growth rate of the conventional melt solidification method. It turned out that it can be raised in. Further, 55.0 mol% BaTiO ₃ -45.0 mol% P obtained by a sintering method using a seed crystal.
The porosity of the bTiO ₃ single crystal was reduced to 5.1% by volume. When the sample was etched in an HCl-HF solution to measure the dislocation density, it was 1 × 10 ⁴ / cm ² .

Example 11 TiO ₂ (26.7288)
g), PbO (0.3720 g) and BaCO ₃ (6
5.4498 g) were wet-mixed, dried and dried at 1100 ° C. for 5 hours.
This is calcined for a period of time, pulverized and molded (diameter 20 m).
m disk shape). In the green compact formed at this time, the molar ratio of the contained elements is (Ba + Pb) / Ti =
0.9960. This was sintered at 1330 ° C. for 10 hours to obtain a sintered body. This sintered body has an average particle size of about 2.
It is composed of coarse crystal grains of 6 mm, and the composition of the sintered body is 99.5 mol% BaTiO ₃ -0.5 mol% PbT
It has been a iO _3. Coarse crystal grains were taken out from the sintered body as seed crystals, and the (001) plane of the crystal grains was cut out to finish the surface roughness Ra = 0.2 nm and the flatness λ / 2. Further, an electron diffraction image of the coarse crystal grains was measured, and it was confirmed that the crystal grains were single crystals having a very uniform crystal orientation. This electron beam diffraction image is shown in FIG.

On the other hand, the same composition was prepared by adding a diameter of 10 mm × a thickness of 20 mm.
mm, and sintered at 1250 ° C. for 3 hours to obtain 99.5 mol% BaTiO ₃ having a relative density of 96.8%.
A −0.5 mol% PbTiO ₃ sintered body was obtained. The average grain size of the crystal grains constituting the sintered body was about 6 μm. The molar ratio of the elements contained in this sintered body is (Ba + Pb) / Ti =
0.9960. The end face of the sintered body is mirror-finished to a surface roughness Ra of 0.2 nm and a flatness of λ / 2, and both polished surfaces of the seed crystal and the sintered body are washed with acetone,
A mixed solution of BaCl ₃ and TiOCl ₂ (solution having a mixing ratio of 1: 0.5) was applied to the bonding interface and bonded. While maintaining this state, it was kept at 1300 ° C. for 30 hours in an oxygen atmosphere to perform single crystallization without melting. After the growing treatment, a single crystal was formed from the surface bonded to the seed crystal to about 14 mm.

From the results, the growth rate was 0.47 mm /
h, which indicates that the growth can be performed at a much higher speed than the growth speed of the conventional melt solidification method. Further, 99.5 mol% of BaTiO ₃ -0.0.9 obtained by a sintering method using a seed crystal.
The pore content of the 5 mol% PbTiO ₃ single crystal was 0.8% by volume, and the dislocation density was determined by etching in a HCl-HF solution. As a result, it was 2 × 10 ² / cm ² . The measurement results of X-ray diffraction performed on this sample are shown in FIG. 3A (before single crystallization) and FIG. 3B (after single crystallization). (Note that peak in the vicinity of 2 [Theta] = 45 ° in FIG. 3 (b) - the click is found two, the other - in order to characteristic X-ray of the target are separated into K [alpha ₁ and K [alpha _2.)

(Embodiment 12) As in Embodiment 3, TSSG
A commercially available BaTiO ₃ single crystal produced by the method
1) The surface was cut into 5 × 5 × 0.5 mm, and this surface was polished to a surface roughness Ra = 0.3 nm and flatness λ / 4 to obtain a seed crystal. On the other hand, BaTiO ₃ (Ba
/Ti=0.9945) Powder and PbT prepared by solid phase method
iO ₃ (Pb / Ti = 0.9952)
By molding it together with a mixing ratio of the mole-to 30.0 moles pot grinding (disc shape with a diameter of 16 mm), 1 hour at 1200 ℃ O ² -HIP (atmosphere 20%
O ² , pressure 98MPa) sintered and relative density 99.96%
70.0 mol% of BaTiO ₃ -30.0 mol% of PbT
An iO ₃ sintered body was produced. The obtained sintered body was composed of crystal grains having an average particle size of about 4 μm. The molar ratio of the elements contained in the sintered body is (Ba + Pb) /Ti=0.9947
It was. The end face of the sintered body is made to have a surface roughness Ra = 0.3n.
After the mirror surface was finished to a m and a flatness of λ / 4, the polished surfaces of the seed crystal and the sintered body were washed with acetone, and then both were mechanically joined. Each of the bonded sample and the PZT sintered body was placed on a setter and further covered with an MgO crucible to form an atmosphere containing Pb. While maintaining this state, the substrate was kept at 1330 ° C. for 20 hours in an oxygen atmosphere to perform single crystallization without melting. After the growth treatment, a single crystal was formed from the surface bonded to the seed crystal to about 12 mm. The pore content in the formed single crystal was 3.8% by volume. When the sample was etched in an HCl-HF solution and the dislocation density was examined, it was 7 × 10 ³ / cm ² .

Example 13 TiO ₂ (26.6246)
g), PbO (3.7200 g) and BaCO ₃ (6
2.4988g), and after wet-drying, dried at 1100 ° C for 5 minutes.
This is calcined for a period of time, pulverized and molded (diameter 20 m).
m disk shape). In the green compact formed at this time, the molar ratio of the contained elements is (Ba + Pb) / Ti =
It was 0.9999. This was sintered at 1300 ° C. for 10 hours to obtain a sintered body. This sintered body has an average particle size of about 2.
It is composed of 2 mm coarse crystal grains, and the composition of the sintered body is 95.0 mol% BaTiO ₃ -5.0 mol% PbT
It has been a iO _3. Coarse crystal grains were taken out from the sintered body as seed crystals, and the (111) plane of the crystal grains was cut out and finished to have a surface roughness Ra of 0.3 nm and a flatness of λ / 4.

On the other hand, the same composition was prepared by adding 10 mm in diameter × 20
mm, and sintered at 1250 ° C. for 3 hours to obtain 95.0 mol% BaTiO ₃ having a relative density of 98.4%.
A −5.0 mol% PbTiO ₃ sintered body was obtained. The average grain size of the crystal grains constituting the sintered body was about 5 μm. The molar ratio of the elements contained in this sintered body is (Ba + Pb) / Ti =
It was 0.9999. The end face of this sintered body is mirror-finished to a surface roughness Ra of 0.3 nm and a flatness of λ / 4, and both polished surfaces of the seed crystal and the sintered body are washed with acetone.
A mixed solution of BaCl ₃ and TiOCl ₂ (solution having a mixing ratio of 1: 0.5) was applied to the bonding interface and bonded. While maintaining this state, it was kept at 1350 ° C. for 20 hours in an oxygen atmosphere to perform single crystallization without melting. After the growth treatment, a single crystal was formed from the surface bonded to the seed crystal to about 12 mm.

From the results, it was found that the growing speed was 0.60 mm /
h, which indicates that the growth can be performed at a much higher speed than the growth speed of the conventional melt solidification method. Further, 95.0 mol% of BaTiO ₃ -5. Obtained by a sintering method using a seed crystal.
The pore content of the 0 mol% PbTiO ₃ single crystal was 0.5% by volume, and the dislocation density was determined by etching in an HCl-HF solution. As a result, it was 5 × 10 ² / cm ² .

Example 14 TiO ₂ (26.8908)
g), PbO (3.7200 g) and BaCO ₃ (6
2.4988g), and after wet-drying, dried at 1100 ° C for 5 minutes.
This is calcined for a period of time, pulverized and molded (diameter 20 m).
m disk shape). In the green compact formed at this time, the molar ratio of the contained elements is (Ba + Pb) / Ti =
0.9990. This was sintered at 1300 ° C. for 10 hours to obtain a sintered body. This sintered body has an average particle size of about 2.
The sintered body has a composition of 95.0 mol% BaTiO ₃ -5.0 mol% PbT.
It has been a iO _3. Coarse crystal grains were taken out from the sintered body as seed crystals, and the (001) plane of the crystal grains was cut out to finish the surface roughness Ra = 0.3 nm and the flatness λ / 4.

On the other hand, the same composition was prepared by adding a diameter of 10 mm and a thickness of 20 mm.
mm, and sintered at 1250 ° C. for 3 hours to obtain 95.0 mol% BaTiO ₃ having a relative density of 98.7%.
A −5.0 mol% PbTiO ₃ sintered body was obtained. The average grain size of the crystal grains constituting the sintered body was about 6 μm. The molar ratio of the elements contained in this sintered body is (Ba + Pb) / Ti =
0.9990. The end face of this sintered body is mirror-finished to a surface roughness Ra of 0.3 nm and a flatness of λ / 4, and both polished surfaces of the seed crystal and the sintered body are washed with acetone.
A mixed solution of BaCl ₃ and TiOCl ₂ (solution having a mixing ratio of 1: 0.5) was applied to the bonding interface and bonded. While maintaining this state, it was kept at 1350 ° C. for 30 hours in an oxygen atmosphere to perform single crystallization without melting. After the growth treatment, a single crystal was formed from the surface bonded to the seed crystal to about 7 mm.

From the results, it was found that the growing speed was 0.23 mm /
h, which indicates that the growth can be performed at a much higher speed than the growth speed of the conventional melt solidification method. Further, 95.0 mol% of BaTiO ₃ -5. Obtained by a sintering method using a seed crystal.
The pore content of the 0 mol% PbTiO ₃ single crystal was 0.6% by volume, and the dislocation density was determined by etching in an HCl-HF solution. The result was 1 × 10 ⁴ / cm ² .

(Example 15) Ba produced by a wet method
TiO ₃ (Ba / Ti = 0.9954) powder and PbTi
O ₃ (Pb / Ti = 1.0000) powder and CaTiO ₃
(Ca / Ti = 1.0000) powder in order of 70.0: 2
The mixture was wet-mixed at a molar ratio of 9.0: 1.0, and was molded (disc shape having a diameter of 20 mm). At this time, in the green compact formed, the molar ratio of the contained elements is (Ba + Pb)
/Ti=0.9868. This is 1350 ° C
For 10 hours to obtain a sintered body. This sintered body is composed of coarse crystal grains having an average particle size of about 3.3 mm, and the composition of the sintered body is 70.0 mol% BaTiO ₃ -29.0 mol% PbTiO ₃ -1.0 mol% CaTiO ₃ was found. Coarse crystal grains are taken out from the sintered body as seed crystals, and the (001) plane of the crystal grains is cut out to obtain a surface roughness R.
a = 0.3 nm and flatness λ / 4.

On the other hand, the same composition was prepared by adding 10 mm in diameter × 20 thickness.
mm, and sintered at 1250 ° C. for 3 hours for 70.0 mol% BaTiO ₃ having a relative density of 98.9%.
−29.0 mol% PbTiO ₃ −1.0 mol% CaTi
An O ₃ sintered body was obtained. The average grain size of the crystal grains constituting the sintered body was about 6 μm. The molar ratio of the elements contained in this sintered body was (Ba + Pb) /Ti=0.9868. The end face of this sintered body is mirror-finished to a surface roughness Ra of 0.3 nm and a flatness of λ / 4. Bonding was performed at 1200 ° C. for 1 hour. A PZT sintered body was placed on a setter together with the joined sample, and a lead atmosphere was formed by covering the MgO crucible, and single crystallization was performed at 1350 ° C. for 50 hours. After the growth treatment, a single crystal was formed from the surface bonded to the seed crystal to about 11 mm.

From the results, it was found that the growing speed was 0.22 mm /
h. 70.0 mol% Ba obtained by sintering method
TiO ₃ -29.0 mol% PbTiO ₃ -1.0 mol%
The pore content of the CaTiO ₃ single crystal was 4.1% by volume, and the dislocation density was determined by etching in an HCl-HF solution to find that it was 1 × 10 ⁴ / cm ² .

(Comparative Example 1) TiO_Two (27.652
g), PbO (3.7200 g) and BaCO_Three(6
2.4988 g) were wet-mixed, dried and dried at 1110 ° C. for 5 hours.
This is calcined for a time and crushed and molded (diameter 16m).
m disk shape). The green compact formed at this time
And the molar ratio of the contained elements is (Ba + Pb) / Ti =
It was 0.9800. This at 1350 ° C for 30 hours
95.0 mol% BaTiO _Three -5.0 mol%
PbTiO_Three A sintered body was obtained. This sintered body has a small average particle size.
Or 50μm crystal grains, used as seed crystals
To obtain a single crystal large enough to be
Was. For this reason, commercially available BaTi grown by the TSSG method
O_Three The same processing as in Example 3 was performed on the (100) plane of the single crystal.
Was used as a seed crystal.

On the other hand, the same composition was prepared by adding 10 mm in diameter × 10 mm in thickness.
mm, and sintered at 1250 ° C. for 3 hours to obtain 95.0 mol% BaTiO ₃ having a relative density of 98.1%.
A −5.0 mol% PbTiO ₃ sintered body was obtained. The average grain size of the crystal grains constituting the sintered body was about 12 μm. The molar ratio of the elements contained in this sintered body is (Ba + Pb) / Ti
= 0.9800. The end face of this sintered body was subjected to surface roughness Ra = 0.4 nm and flatness λ / 6 in the same manner as in Example 3.
After polishing both surfaces of the seed crystal and the sintered body with acetone, a 2N HNO ₃ solution was applied to the bonding interface and bonded. While maintaining this state, it was kept at 1370 ° C. for 50 hours in an oxygen atmosphere to perform single crystallization without melting.

After the single crystal growing process, the crystal had grown only up to 100 μm from the surface joined with the seed crystal. From this result, it was found that the growth rate was 2 × 10 ⁻³ mm / h, and single crystallization hardly proceeded.

Comparative Example 2 BaTiO by Coprecipitation Method_Three 
(Ba / Ti = 1.000) and PbTiO_Three (Pb
/Ti=1.0100) powder was prepared, and 90.0 mol
The mixture was mixed at a rate of 10.0 mol. Pot this mixed powder
This is crushed in a mill and molded (with a diameter of 16 mm).
Disk shape). The content of the green compact formed at this time is
The molar ratio of the elements is (Ba + Pb) /Ti=1.0010
It was. This was sintered at 1350 ° C. for 10 hours to obtain 9
0.0 mol% BaTiO_Three -10.0 mol% PbTiO
_Three A sintered body was obtained. This sintered body is fine with an average particle size of about 3 μm.
It is composed of various crystal grains and is suitable for use as a seed crystal.
A single crystal of an appropriate size could not be obtained. There
In the same manner as in Comparative Example 1, it was grown by a commercial TSSG method.
BaTiO_Three The single crystal was used as a seed crystal. Meanwhile, the same formulation
Into a disk shape of 10mm diameter x 15mm thickness
And sintered at 1250 ° C. for 3 hours to obtain a relative density of 97.8%.
90.0 mol% BaTiO_Three -10.0 mol% PbTi
O_Three A sintered body was obtained. Molar ratio of elements contained in this sintered body
Was (Ba + Pb) /Ti=1.0010.
The end face of this sintered body was subjected to surface roughness Ra =
Mirror finish to 0.4nm, flatness λ / 6,
After washing the polished surfaces of the crystal and sintered body with acetone,
BaCl _Three And TiOCl_Two Mixed solution (mixing ratio 1:
1 solution) and bonded. While maintaining this state
And kept at 1390 ° C for 30 hours in an oxygen atmosphere to
Single crystallization was performed under melting. After the single crystal growing process,
About 1 to 2 grain width from the joined surface (about 5 to 10 μm
) Is only incorporated into the single crystal, and almost no single crystallization occurs.
Nothing happened.

Comparative Example 3 BaTiO by TSSG Method
_{A 3-} PbTiO ₃ single crystal was grown. Commercially available BaTiO ₃ powder, TiO ₂ powder, and P
bTiO ₃ powder was used. The raw material powder is BaTiO ₃ : T
A sintered body was prepared using a molar ratio of iO ₂ : PbTiO ₃ = 1: 0.5: 0.01, and the sintered body was put in a platinum crucible to melt the raw material by high frequency induction heating. Growth temperature is 14
A BaTiO ₃ seed crystal of <100> orientation attached to a platinum holder at 40 ° C. is immersed in this melt,
The temperature was lowered at a rate of 0.4 ° C./h with rotation of m, and the crystal was grown at a rate of 0.1 mm / h. About 200
After a lapse of time, when the temperature reached around 1330 ° C. (eutectic temperature), the pulling was terminated. The obtained crystal has a diameter of 25 mm and a length of 1.
It was 6 mm (volume 7.9 cm ³ ). The inside of the crystal has a porous structure in which many voids of several μm to several tens of μm are formed due to Pb evaporation during growth (porosity is 8% by volume). Many occurred. The dislocation density in the crystal is 2
× 10 ⁶ / cm ² , and according to the present invention, BaTiO ₃ —Pb
The dislocation density was higher than that of the TiO ₃ single crystal.
Further, the productivity is 0.04 cm ³ / h,
aTiO ₃ about 1/10 compared to the -PbTiO ₃ system single crystal
It's just 0.

The present inventors have also obtained the present invention.
BaTiO_Three -PbTiO_Three The crystallinity of single crystals
Of the BaTiO of the present invention_Three -PbT
iO _Three A system single crystal must have very good crystallinity.
It turned out. Uniform orientation from X-ray diffraction and electron diffraction
It was confirmed that the single crystal was uniform. Also,
Impurity or case due to low dislocation density
It was confirmed that the crystal had few child defects,
Was also very small.

Further, the BaTiO of the present invention_Three -PbTi
O_Three Other physical properties such as dielectricity, piezoelectricity, and pyroelectricity of single crystal
Was also examined, BaTiO_Three -PbT
iO _Three Regarding the physical properties of the system single crystal,
And excellent characteristics were observed. It is BaTiO_Three Polycrystalline
Needless to say, PZ which is currently used as standard
T (Pb (Ti, Zr) O_Three ) Made by polycrystal or TSSG method
BaTiO made_ThreeIt surpasses the properties of single crystals.
Was.

BaTiO of the present invention_Three -PbTiO_Three System simple
Considering crystals from the perspective of piezoelectric materials,
Of the usable temperature range and lead-containing
One of the strong points is that it has achieved
it can. BaTiO_Three Polycrystals have a Curie temperature (T_c )But
About 120 ° C, BaTiO_Three For devices using polycrystals
Curie temperature (T_c ) Limited use
The narrow working temperature range has been a practical difficulty in the past. This
In contrast, the BaTiO of the present invention_Three -PbTiO _Three Simple connection
The crystal is BaTiO_Three Curie temperature (T_c )
And the usable temperature range can be further expanded.

In order to reduce the load on the global environment,
In recent years, it has been required to reduce the amount of lead used in industrial products.
However, the BaTiO of the present invention_Three -PbTiO_Three Simple connection
PZT, which is currently the mainstream of piezoelectric materials
Compared to polycrystalline, first, due to the difference in composition,
Can be used, and the piezoelectric characteristics
Required to achieve the same effect by improving
It can be seen that the amount of use of various piezoelectric materials can be significantly reduced
You. In addition, PZT, which generally aims to reduce lead
An alternative promising material is BaTiO_Three Polycrystalline, Bi
_0.5 Na_0.5 TiO _Three Polycrystalline, (Na_0.5 K_0.5 ) Nb
O_Three Although polycrystal is considered, PZT has a piezoelectric constant d₃₃
= 300-400 (× 10^-12 C / N), electromechanical coupling
Coefficient k₃₃= 0.6 to 0.7, whereas BaTi
O_Three Polycrystal has a piezoelectric constant d₃₃= 120 (× 10^-12 C /
N), electromechanical coupling coefficient k₃₃= 0.4-0.5,
Bi_{0. Five} Na_0.5 TiO_Three Polycrystal has a piezoelectric constant d₃₃= 1
10 (× 10^-12 C / N), electromechanical coupling coefficient k₃₃=
0.4 to 0.6, which is satisfactory for its piezoelectric characteristics.
It was not something that could be done. In addition, BaTiO_Three -PbTi
O_Three Think of polycrystalline as a piezoelectric material
Also, the piezoelectric characteristics of the PZT polycrystal or the BaTiO of the present invention
_Three -PbTiO_Three It is significantly inferior to the system single crystal.
Therefore, it is impossible for a polycrystal to have a drastic improvement in piezoelectric characteristics.
No.

In each of the embodiments of the present invention described above, in particular, the BaTi
Table 1 shows various piezoelectric characteristics of the O ₃ —PbTiO ₃ single crystal, the general PZT sintered body, the BaTiO ₃ sintered body, and the BaTiO ₃ single crystal grown by the TSSG method.

[0094]

[Table 1]

In the BaTiO ₃ -PbTiO ₃ single crystal of the present invention, as can be seen from Table 1, the Curie temperature (T _c ) increases as the Pb content increases, and the Curie temperature up to about 300 ° C. You can choose.
Further, the BaTiO ₃ -PbTiO ₃ single crystal obtained by the sintering method has a smaller dielectric loss than a normal BaTiO ₃ sintered body, and a sharp increase in the electromechanical coupling coefficient accompanying disappearance of the large-angle grain boundary grain boundary causes It can be seen that the amount of induced strain at the time of applying an electric field is increased, and extremely excellent piezoelectric characteristics are exhibited.

Next, the BaTiO ₃ -PbTiO of the present invention is used.
A piezoelectric actuator (piezoelectric vibrator) using a _3- system single crystal and a liquid ejection head using the piezoelectric actuator will be described with reference to FIG. FIG. 2 (a)
The liquid discharge head 11 illustrated in FIGS. 1 and 2B includes a plurality of liquid discharge ports 12, a liquid chamber 13 provided corresponding to each liquid discharge port 12, and a piezoelectric type head provided for each of the liquid chambers 13. and an actuator 19, the piezoelectric actuator 19 is at least BaTiO ₃ -PbTiO ₃ system Pt formed on the surface of the piezoelectric element 14 and the piezoelectric body 14 including a layer of single crystal, Au, electrodes such as Al (not And a vibration plate 17 joined to the piezoelectric body 14 to form a piezoelectric vibrator. The liquid discharge ports 12 of the liquid discharge head 11 are formed at predetermined intervals in the nozzle plate 15, and the liquid chamber 13 is formed in the substrate section 16 with the liquid discharge ports 1.
2 are formed in parallel to correspond to each other,
Each of the liquid discharge ports 12 and the corresponding liquid chamber 13 are provided in the substrate section 1.
6 via a liquid flow path 16a. An opening 16b is formed on the upper surface of the substrate 16 corresponding to each of the liquid chambers 13, and a diaphragm 17 is formed on the upper surface of the substrate 16 so as to cover the opening 16b. A piezoelectric body 14 is arranged on the liquid crystal chamber 13 so as to correspond to each liquid chamber 13.

The liquid discharge head 1 configured as described above
1, when a driving signal is externally applied to the piezoelectric actuator 19, the piezoelectric actuator 19
Is driven to pressurize the liquid in the corresponding liquid chamber 13,
The liquid is discharged as liquid droplets from the liquid discharge port 12 communicating with the third liquid.

By using a BaTiO ₃ —PbTiO ₃ single crystal, which is a piezoelectric material having a low lead content, as a piezoelectric material constituting a piezoelectric actuator (piezoelectric vibrator), the characteristics of the PZT can be greatly surpassed. Excellent piezoelectric characteristics can be obtained at low cost, and an environmentally friendly piezoelectric actuator (piezoelectric vibrator) and liquid discharge head can be manufactured.

[0099]

As described above, according to the present invention,
BaTiO ₃ —PbTiO ₃ based green compact or sintered body is
A single crystal can be formed by heating to a predetermined composition in which the number of moles of Pb is smaller than the number of moles of Ba and in a predetermined temperature range while maintaining a non-molten state, thereby enabling stable single crystal growth. And the growth rate of the single crystal can be promoted.

Further, a single crystal is obtained by heating a BaTiO ₃ -PbTiO ₃ -based green compact or sintered body having a (Ba + Pb) / Ti ratio in a predetermined composition range in a predetermined temperature range while maintaining a non-molten state. By doing so, reproducibility of single crystal growth is improved, and stable single crystal growth is enabled.

Further, a BaTiO ₃ single crystal or Ba
The TiO ₃ -PbTiO ₃ single crystal as a seed crystal, as well to produce a BaTiO ₃ -PbTiO ₃ polycrystal compositionally adjusted, the heat treatment by bonding polycrystal of the green compact or sintered seed crystal By performing this, stable single crystallization occurs from the joint portion with the seed crystal of the green compact or the sintered body, a high-quality BaTiO ₃ —PbTiO ₃ single crystal is obtained, and the reproducibility of single crystal growth is improved. improves. The growth rate of the single crystal by this sintering method is equal to or exceeds that of the Melt-Growth method.

Also, since a large number of samples can be processed simultaneously by the sintering method, not only can the production cost be greatly reduced, but also the dislocation density in the crystal is very small and high quality can be achieved. Productivity and characteristics can be compatible.

Further, the BaTiO of the present invention_Three -PbTi
O_Three Single crystals far surpass the properties of existing PZT sintered compacts
To meet the purpose of reducing harmful substances such as Pb in PZT.
Pb-less piezoelectric material comparable to existing PZT-based materials
BaTiO with good properties _Three -PbTiO_Three Single crystal
Can be provided. Also, the Pb content increases
As the Curie temperature rises, the
Curie temperature can be selected as appropriate,
No temperature issues. BaTiO by sintering method_Three −
PbTiO_Three Single crystals have low dielectric loss and large tilt boundaries
Dramatic increase in electromechanical coupling coefficient due to disappearance of grain boundaries
The amount of induced strain at the time of applying an electric field increases,
It shows the electrical characteristics.

[Brief description of the drawings]

FIG. 1 is a process chart showing an example of a method for producing a BaTiO ₃ —PbTiO ₃ single crystal of the present invention.

FIG. 2 is a view showing a liquid ejection head of the present invention,
(A) is a perspective view, and (b) is a cross-sectional view taken along line AA of (a).

FIG. 3 (a) shows BaTiO ₃ —PbTiO before a seed crystal is bonded to form a single crystal in Example 11 of the present invention.
_FIG. 7B is an X-ray diffraction pattern of a BaTiO ₃ -PbTiO ₃ single crystal after bonding a seed crystal and forming a single crystal in Example 11 in the same manner as in Example 11;
It is.

FIG. 4 is an electron diffraction image of a BaTiO ₃ —PbTiO ₃ single crystal after single crystallization used as a seed crystal in Example 11 of the present invention.

[Explanation of symbols]

One crystal (BaTiO ₃ -PbTiO ₃ system single crystal) ₃ BaTiO 3 -PbTiO 3 based sintered body 5 single crystal portion 7 polycrystalline portion 11 the liquid discharge head 12 fluid outlet 13 liquid chamber 14 piezoelectric layer 15 nozzle Plate 16 Substrate 17 Vibration plate 19 (piezoelectric) actuator

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) H01L 41/08 C (72) Inventor Tetsuro Fukui 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Akio Ikesue 2-27-7, Rokuno, Atsuta-ku, Nagoya-shi, Aichi F-term (reference) 4G077 AA02 BC42 BC43 CA03 CA09 EA02 EA07 HA11 JA08

Claims (22)

[Claims] A single crystal is obtained by heating a BaTiO ₃ -PbTiO ₃ -based green compact or sintered body in which the mole number of Pb is smaller than the mole number of Ba while keeping it in a non-molten state. BaTiO ₃ —PbTi characterized by the following:
O ₃ single crystal. 2. A dislocation density of 10 ² / cm ² or more and 10 ⁶ or more.
B / cm ² or less, and a pore content is in a range of 1 vol ppm or more and 5 vol% or less.
aTiO ₃ -PbTiO ₃ system single crystal. 3. The BaT according to claim 1, wherein the content of PbTiO ₃ is 45 mol% or less.
iO ₃ -PbTiO ₃ system single crystal. 4. The BaT according to claim 1, wherein the content of PbTiO ₃ is 30 mol% or less.
iO ₃ -PbTiO ₃ system single crystal. 5. The BaT according to claim 1, wherein the content of PbTiO ₃ is 25 mol% or less.
iO ₃ -PbTiO ₃ system single crystal. 6. The BaT according to claim 1, wherein the BaT has a volume of 1 mm ³ or more.
iO ₃ -PbTiO ₃ system single crystal. 7. A dislocation density of 10 ² / cm ² or more and 10 ⁶ or more.
Pieces / cm ² or less, BaTiO ₃ -P pores content, characterized in that in the range of 5 vol% or more 1 ppm by volume
bTiO ₃ single crystal. 8. The BaTiO ₃ − according to claim 7, wherein the content of PbTiO ₃ is 45 mol% or less.
PbTiO ₃ single crystal. 9. A piezoelectric actuator comprising a layer made of the BaTiO ₃ —PbTiO ₃ based single crystal according to claim 1. Description: 10. A liquid discharge head comprising the piezoelectric actuator according to claim 9. 11. The molar ratio of elements contained in a BaTiO ₃ —PbTiO ₃ based green compact or sintered body in which the molar number of Pb is smaller than the molar number of Ba is 0.9800 <(B
a + Pb) / Ti <1.0000, and including a step of heating the green compact or the sintered body in a non-molten state to form a single crystal, thereby forming a single crystal.
manufacturing method of iO ₃ -PbTiO ₃ system single crystal. 12. The molar ratio of elements contained in the green compact or the sintered body is 0.9900 <(Ba + Pb) / Ti <
12. The range of 1.0000.
BaTiO ₃ -PbTiO ₃ system method for manufacturing a single crystal according. 13. The molar ratio of elements contained in the green compact or the sintered body is 0.9950 ≦ (Ba + Pb) / Ti ≦
The BaTiO according to claim 11, which is in the range of 0.9999.
_A method for producing a _3- PbTiO ₃ single crystal. 14. The compact or sintered body of PbTiO.
BaTiO ₃ -PbTiO ₃ system method for producing a single crystal according to claim 11, wherein the _third content is 45 mol% or less. 15. The compact or sintered body of PbTiO.
BaTiO ₃ -PbTiO ₃ system method for producing a single crystal according to claim 11, wherein the _third content is less than 30 mol%. 16. The compact or sintered body of PbTiO.
BaTiO ₃ -PbTiO ₃ system method for producing a single crystal according to claim 11, wherein the _third content is less than 25 mol%. 17. The compact or sintered body is heated to 1200 ° C.
BaTiO ₃ -PbTiO ₃ system method for producing a single crystal according to claim 11, characterized in that it comprises a step of single crystal by heating at a temperature range of 1400 ° C. or less. 18. The method of claim 11, wherein the growing the by generating vapor containing Pb by inserting the lead-containing compound in the furnace during the single crystal growth process BaTiO ₃ -PbTiO ₃ system single crystal BaTiO ₃ -PbTiO
Method for producing _3- series single crystal. 19. The BaTiO ₃ —P according to claim 11, further comprising a step of heating the green compact or the sintered body in a non-molten state in a lead atmosphere while heating to form a single crystal.
A method for producing a bTiO ₃ single crystal. 20. BaTiO_Three System single crystal or BaT
iO_Three -PbTiO _Three System single crystal as seed crystal, average particle size
Consisting of crystal grains of 20 μm or less, relative density of 95% or less
BaTiO on top_Three -PbTiO_Three -Based sintered body
{100}, {110} or {111} faces of the crystal
By heating while maintaining the non-molten state
BaTiO characterized by single crystallization_Three -PbTi
O_Three A method for producing a system single crystal. 21. The molar ratio of elements contained in the BaTiO ₃ —PbTiO ₃ based sintered body is 0.9950 ≦ (Ba +
BaTiO ₃ -PbTiO ₃ system method for producing a single crystal according to claim 20, wherein in the range of Pb) /Ti≦0.9999. 22. A BaTiO ₃ -PbTiO ₃ single crystal is grown by inserting a lead-containing compound into a furnace during the single crystal growing process to generate a Pb-containing vapor. BaTiO ₃ -PbTiO
Method for producing _3- series single crystal.